<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>

    <style>
    *{
        margin:0;
        padding:0;
    }

    .wrapper{
        /* height:900px; */
        background-color: gray;
        overflow: hidden;
    }
    .box {
        float: left;
        
        height: 900px;
    }
    .center {
        width: 100%;
        background-color: green;
    }
    .left{
        width: 100px;
        background-color: red;
        margin-left: -100%;
    }
    .right{
        width: 100px;
        background-color: blue;
        margin-left: -100px;
    }

    </style>
</head>
<body>
    <div class="wrapper">

        <div class="box center"></div>
        <div class="box left"></div>
        <div class="box right"></div>

    </div>
</body>
</html>